export default {
  // 为当前模块开启命名空间
  namespaced: true,

  // 模块的 state 数据
  state: () => ({
    // 购物车的数组，用来存储购物车中每个商品的信息对象
    // 每个商品的信息对象，都包含如下 6 个属性：
    // { goods_id, goods_name, goods_price, goods_count, goods_small_logo, goods_state }
    cart: JSON.parse(uni.getStorageSync('cart') || '[]')
  }),

  // 模块的 mutations 方法
  mutations: {
    addToCart(state, goods) {
      const findResult = state.cart.find(x => x.goods_id === goods.goods_id)


      if (!findResult) {
        state.cart.push(goods)
      } else {
        findResult.goods_count++
      }
      
      this.commit('m_cart/saveToStorage')
    },
    saveToStorage(state){
      uni.setStorageSync('cart',JSON.stringify(state.cart))
    },
    //更新购物车中商品的勾选状态
    updateGoodsState(state,goods){
      const findResult = state.cart.find(x => x.goods_id === goods.goods_id)
      
      if(findResult){
        findResult.goods_state = goods.goods_state
        
        this.commit('m_cart/saveToStorage')
      }
    },
    //更新商品的数量
    updateGoodsCount(state,goods){
      const findResult = state.cart.find(x => x.goods_id === goods.goods_id)
      
      if(findResult){
        findResult.goods_count = goods.goods_count
        
        this.commit('m_cart/saveToStorage')
      }
    },
    // 根据 Id 从购物车中删除对应的商品信息
    removeGoodsById(state, goods_id) {
      // 调用数组的 filter 方法进行过滤
      state.cart = state.cart.filter(x => x.goods_id !== goods_id)
      // 持久化存储到本地
      this.commit('m_cart/saveToStorage')
    },
    //更新购物车中所有商品的勾选状态
    updateAllGoodsState(state, newState){
      state.cart.forEach(x => x.goods_state = newState)
      
      // 持久化存储到本地
      this.commit('m_cart/saveToStorage')
    }
  },

  // 模块的 getters 属性
  getters: {
    //购物车所有商品的总数量
    total(state) {
      // let c = 0
      // state.cart.forEach(x => c += x.goods_count)
      // return c
     
     return state.cart.reduce( (total,item) => total += item.goods_count,0) 
    },
    //购物车已勾选商品的总数量
    checkedCount(state){
      return state.cart.filter(x => x.goods_state).reduce( (total,item) => total += item.goods_count , 0) 
    },
    checkedGoodsAmount(state){
      return state.cart.filter(x => x.goods_state).reduce((total,item) => total += item.goods_count * item.goods_price, 0).toFixed(2)
    }
  },
}
